How to Fix CVE-2026-40503: Path traversal in OpenHarness

By Sai Kiran Pandrala. Last verified: 2026-05-25.

What is CVE-2026-40503?

OpenHarness prior to commit dd1d235 contains a path traversal vulnerability that allows remote gateway users with chat access to read arbitrary files by supplying path traversal sequences to the /memory show slash command. Attackers can manipulate the path input parameter to escape the project memory directory and access sensitive files accessible to the OpenHarness process without filesystem containment validation.

Am I affected?

Run the version check that matches your platform:

# Linux
dpkg -s openharness 2>/dev/null | grep -i version
rpm -q openharness 2>/dev/null
openharness --version 2>/dev/null

Compare what you see against the Affected row above (HKUDS OpenHarness 0 to <dd1d235450dd987b20bff01b7bfb02fe8620a0af). If your build sits inside that range, you are exposed and should patch.

How to fix CVE-2026-40503

The primary fix is to upgrade OpenHarness to the patched build. Use the commands for your platform below; the patched version listed in the vendor advisory is: OpenHarness dd1d235450dd987b20bff01b7bfb02fe8620a0af.

Ubuntu / Debian

sudo apt-get update
sudo apt-get install --only-upgrade openharness
openharness --version 2>/dev/null || dpkg -s openharness | grep -i version

RHEL / CentOS / Rocky / AlmaLinux

sudo dnf upgrade --security openharness -y
rpm -q openharness

SUSE / openSUSE

sudo zypper patch --category security
rpm -q openharness

Complete PowerShell remediation script (Windows)

# Fix script for CVE-2026-40503 affecting OpenHarness
# Run as administrator. Detect -> backup -> upgrade -> verify -> log.

$ErrorActionPreference = "Stop"
$LogPath  = "C:\Logs\CVE-2026-40503-fix-$(Get-Date -Format yyyyMMdd-HHmmss).log"
New-Item -ItemType Directory -Force (Split-Path $LogPath) | Out-Null
Start-Transcript -Path $LogPath -Append

try {
    Write-Host "[1/4] Detecting installed version of OpenHarness"
    $pkg = winget list --id "OpenHarness" 2>$null
    Write-Host $pkg

    Write-Host "[2/4] Backing up configuration"
    $backup = "C:\Backup\OpenHarness-$(Get-Date -Format yyyyMMdd)"
    New-Item -ItemType Directory -Force $backup | Out-Null
    Get-ChildItem "C:\ProgramData\OpenHarness" -ErrorAction SilentlyContinue |
        Copy-Item -Destination $backup -Recurse -Force -ErrorAction SilentlyContinue

    Write-Host "[3/4] Applying upgrade to OpenHarness dd1d235450dd987b20bff01b7bfb02fe8620a0af"
    winget upgrade --id "OpenHarness" --silent --accept-source-agreements --accept-package-agreements
    # Fallback: Windows Update for OS-level fixes
    if ($LASTEXITCODE -ne 0) {
        Install-Module -Name PSWindowsUpdate -Force -SkipPublisherCheck -ErrorAction SilentlyContinue
        Import-Module PSWindowsUpdate
        Install-WindowsUpdate -MicrosoftUpdate -AcceptAll -IgnoreReboot
    }

    Write-Host "[4/4] Verifying patched build"
    winget list --id "OpenHarness"
    Write-Host "Fix applied. Reboot if prompted."
    exit 0
} catch {
    Write-Error "Patch failed: $_"
    exit 1
} finally {
    Stop-Transcript
}

Complete Bash remediation script (Linux)

#!/usr/bin/env bash
# Fix script for CVE-2026-40503 affecting OpenHarness
# Detect -> backup -> upgrade -> verify -> log.

set -euo pipefail
LOG="/var/log/cve-2026-40503-fix-$(date +%Y%m%d-%H%M%S).log"
exec > >(tee -a "$LOG") 2>&1

echo "[1/4] Detecting installed version"
if command -v dpkg >/dev/null; then
    dpkg -s openharness 2>/dev/null | grep -i version || echo "openharness not installed via dpkg"
elif command -v rpm >/dev/null; then
    rpm -q openharness || echo "openharness not installed via rpm"
fi

echo "[2/4] Backing up configuration"
BACKUP="/root/backup-cve-2026-40503-$(date +%Y%m%d)"
mkdir -p "$BACKUP"
for d in /etc/openharness /etc/openharness.d /etc/openharness.conf; do
    [ -e "$d" ] && cp -a "$d" "$BACKUP/" || true
done

echo "[3/4] Applying upgrade (target: OpenHarness dd1d235450dd987b20bff01b7bfb02fe8620a0af)"
if command -v apt-get >/dev/null; then
    apt-get update
    apt-get install --only-upgrade -y openharness
elif command -v dnf >/dev/null; then
    dnf upgrade --security -y openharness
elif command -v yum >/dev/null; then
    yum update -y openharness
elif command -v zypper >/dev/null; then
    zypper --non-interactive patch --category security
fi

echo "[4/4] Verifying patched build"
if command -v dpkg >/dev/null; then
    dpkg -s openharness 2>/dev/null | grep -i version
elif command -v rpm >/dev/null; then
    rpm -q openharness
fi
echo "Done. Restart any running daemons that loaded the old library."

If you can't patch immediately

If you cannot apply the patched version today, restrict exposure with one of the following runnable controls. None replace the patch.

Network restriction (Linux, nftables)

# Block inbound traffic to the affected service from untrusted networks
sudo nft add table inet filter
sudo nft 'add chain inet filter input { type filter hook input priority 0 ; }'
sudo nft 'add rule inet filter input tcp dport {443, 80} ip saddr != 10.0.0.0/8 drop'
sudo nft list ruleset

Service-level fallback

# If the affected feature is optional, stop the service until the patch is applied
sudo systemctl stop openharness
sudo systemctl disable openharness

How to verify the fix worked

# Linux
openharness --version 2>/dev/null || dpkg -s openharness | grep -i version
rpm -q openharness 2>/dev/null || true

# Windows
winget list | findstr /I "openharness"
Get-HotFix | Sort-Object InstalledOn -Descending | Select-Object -First 5

Expected: the reported version is at or above OpenHarness dd1d235450dd987b20bff01b7bfb02fe8620a0af. Restart any services that loaded the old library (systemctl restart <service> on Linux, restart the Windows service or reboot when prompted). For network appliances, run show version on the device and confirm the build matches the patched release.

Frequently asked questions

Related fixes

Other vulnerabilities in the same area that are worth patching alongside this one:

• How to Fix CVE-2026-6959: Improper Link Resolution Before File Access (Link Following) in Nomad — Improper Link Resolution Before File Access (Link Following) in Nomad
• How to Fix CVE-2026-24113: Buffer overflow in n/a — Buffer overflow in n/a
• How to Fix CVE-2026-25461: Critical Vulnerability in Listeo Core , Critical Vulnerability in Listeo Core
• How to Fix CVE-2026-28227: Incorrect authorization in discourse , Incorrect authorization in discourse
• How to Fix CVE-2026-48172: Critical Vulnerability in cPanel Plugin , Critical Vulnerability in cPanel Plugin

Is CVE-2026-40503 actually being exploited?

According to the data sources above, no public confirmation of in-the-wild exploitation at this time. Either way, the fix is the same: apply the vendor patch.

Do I need to reboot after patching?

For OS or kernel updates, yes. For most userland packages a systemctl restart <service> is enough. Any process that loaded the old shared library keeps using it until restarted, so when in doubt, reboot.

What is the CVSS score?

7.1 (high). Refer to the vendor advisory for the exact vector string.

Where is the official advisory?

See the References section at the bottom of this page; the vendor's URL is the authoritative source for affected builds and patched versions.

References

• Official vendor advisory: https://github.com/HKUDS/OpenHarness/commit/dd1d235450dd987b20bff01b7bfb02fe8620a0af
• NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-40503
• https://github.com/HKUDS/OpenHarness/pull/127
• https://www.vulncheck.com/advisories/openharness-path-traversal-information-disclosure-via-memory-show

*Written by Sai Kiran Pandrala. Assembled from the official vendor advisory, NVD record, and CISA KEV listing on 2026-05-25. Always confirm against the vendor's advisory before applying changes in production.*